BIOL108 Study Guide - Lungfish, Chitin, Haikouella

• School: University of Alberta
• Department: Biology (Biological Sciences)
• Course: BIOL108
• Professor: Randal Arsenault

Document Summary

Burgess beasts - mud dwellers, more epifauna, weird arthropods: anamalacarus & Opabinia, some floaters & swimmers including one early chordate ancestors pikaia. Considered to be basal to all other animals. Other member is placozoa - trichoplax adhaerens. If body of trichoplax or of many sponges is broken up, the individual cells can reassemble to make a functional organism. Have similar body plan, but are not closely related. Most body segments have fleshy lobes (parapodia = not quite feet) that bear many chaetae - bristle. Have clearly differentiated head with sensory antennae and often with eyes. Sedentary either inject substrate, suspension feed, or deposit feed (usually dig burrows and/or construct tubes) Many are free-spawning (eggs and sperm released into water) In some species, modified body sections break off, swim to surface, and explode to release gametes. Trochophore larvae are planktonic with subsequent larvae leading benthic lives (live @ bottom of sea or lake) Morphologically and ecologically much less diverse than polychaetes.